Thermodynamic and thermoeconomic performance analyses and optimization of a novel power and cooling cogeneration system fueled by low-grade waste heat

Yu, Wei; Xu, Yali; Wang, Huitao; Ge, Zhong; Wang, Jianjun; Zhu, Daofei; Xia, Yuchen

doi:10.1016/j.applthermaleng.2020.115667

Cited by 27 publications

(8 citation statements)

References 43 publications

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“…Due to their low or zero ODP, HCFs, including R245fa, have served as transition working fluids to replace CFCs and HCFCs [16,34]. R245fa is widely employed in actual low-grade thermal energy conversion systems, and has been investigated in recent ejector refrigeration performance studies, such as [35,36]. Although, given their GWPs, HFCs are planned to be phased out globally by 2025-2040 [16,34] according to the Montreal Protocol Kigali agreement and Kyoto Protocol [37,38], different baseline and delayed phase-down periods have been granted to developing and/or high ambient temperature countries, including, for example, India [16] and GCC countries [39,40].…”

Section: Solar-assisted Ejector Space Cooling Systemmentioning

confidence: 99%

“…Generator refrigerant outlet temperature, T g ( • C) 85 (range of variation: 80−100) [18,20,21,35,48] Evaporator refrigerant outlet temperature, T e ( • C) 10 (range of variation: 5−16) [18,20,21,25,35,48] Minimum temperature difference ( • C) Generator 10 [25,36] Condenser 3 [32] Ejector Primary nozzle exit to throat effective area diameter ratio, D 2 /D 1 (-) 1 1.7 [20,21] Isentropic efficiency coefficient for primary nozzle, η p (-) 0.95 [25,35,47] Isentropic efficiency coefficient from nozzle exit to section y, η py (-) 0.88 (this study, based on [20,35])…”

Section: Refrigeration Sub-systemmentioning

confidence: 99%

“…Negligible kinetic energy at the primary and secondary flow inlets, and diffuser exit [20,25,32] • Isobaric mixing process between the hypothetical throat (y) and section (m) [20,36] •…”

mentioning

confidence: 99%

“…Friction and mixing losses are accounted for in the form of isentropic efficiencies for the primary and secondary flows, and in the form of a frictional loss coefficient in the constant area mixing section [20,36] The ejector modeling equations are detailed in Appendix B, and the model validation is documented in Section 3.4. The solar collector and refrigeration sub-systems thermodynamic models are described in Sections 3.1 and 3.2 for energy and exergy analysis, respectively, and the system performance metrics in Section 3.3.…”

mentioning

confidence: 99%

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Thermodynamic Performance Investigation of a Small-Scale Solar Compression-Assisted Multi-Ejector Indoor Air Conditioning System for Hot Climate Conditions

Eveloy

Alkendi

2021

Energies

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In year-round hot climatic conditions, conventional air conditioning systems consume significant amounts of electricity primarily generated by conventional power plants. A compression-assisted, multi-ejector space cooling system driven by low-grade solar thermal energy is investigated in terms of energy and exergy performance, using a real gas property-based ejector model for a 36 kW-scale air conditioning application, exposed to annually high outdoor temperatures (i.e., up to 42 °C), for four working fluids (R11, R141b, R245fa, R600a). Using R245fa, the multi-ejector system effectively triples the operating condenser temperature range of a single ejector system to cover the range of annual outdoor conditions, while compression boosting reduces the generator heat input requirement and improves the overall refrigeration coefficient of performance (COP) by factors of ~3–8 at medium- to high-bound condenser temperatures, relative to simple ejector cycles. The system solar fraction varies from ~0.2 to 0.9 in summer and winter, respectively, with annual average mechanical and overall COPs of 24.5 and 0.21, respectively. Exergy destruction primarily takes place in the ejector assembly, but ejector exergy efficiency improves with compression boosting. The system could reduce annual electric cooling loads by over 40% compared with a conventional local split air conditioner, with corresponding savings in electricity expenditure and GHG emissions.

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Section: Solar-assisted Ejector Space Cooling Systemmentioning

confidence: 99%

Section: Refrigeration Sub-systemmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Thermodynamic Performance Investigation of a Small-Scale Solar Compression-Assisted Multi-Ejector Indoor Air Conditioning System for Hot Climate Conditions

Eveloy

Alkendi

2021

Energies

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“…From the perspectives of thermodynamics and economics, a novel combined cooling and power cogeneration system driven by geothermal hot water was analyzed and optimized by Akbari Kordlar and Mahmoudi [27], which was a combination of an organic Rankine cycle and an absorption refrigeration cycle. A novel power and cooling cogeneration system was designed by Yu et al [28] with three separate objectives: minimize the total cost of unit exergy, maximize the thermal efficiency and exergy efficiency. Baumgä rtner et al [29] and Jaber et al [30] analyzed and optimized energy systems from aspects of economy and environment.…”

Section: Introductionmentioning

confidence: 99%

Multi-Objective Optimization of Steam Power System Under Demand Uncertainty

et al. 2021

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There are many uncertain factors, which are critical for the efficient operation of steam power systems (SPSs). Due to the modelling inaccuracy and the changing environment, it is challenging to directly formulate the model for SPS operation. In this paper, a method is proposed to alleviate the influence of small-scale fluctuation by discretizing the uncertainty working condition on the SPS. Moreover, the exergy analysis method is proposed to evaluate the quality of different energy and develop a mixedinteger nonlinear model of SPS considering the economic and exergy objectives. Finally, the ε-constraint method is used to obtain the Pareto front of the multi-objective optimization problem, and the fuzzy decision is used to determine the optimal strategy of the system. By introducing the multi-objective optimization of the SPS model with demand side uncertainty, a flexible scheduling scheme with good economic and exergy objectives is obtained. Comparing with the optimal scheduling without the demandside uncertainty, numerical results indicate the feasibility and effectiveness of the model.

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Economic Analyses of a New Power and Cooling System at Low Temperature Applications

Omprakash,

Shankar Ganesh

2024

Energy Tech

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Recent research suggests that the implementation of more efficient combined cooling and power systems, which enable the cogeneration of electricity and cooling, can enhance the efficiency of hybrid plants. The present investigation is motivated by finding that, in the literature review on combined power and cooling systems, there is very limited information on the coupling of the organic Rankine cycle (ORC) and the ejector refrigeration cycle (ERC) with low sink temperatures. A suggested approach to do this involves using hot exhaust gas and waste heat engines to power an ORC hybrid system. To enhance the ORC–ERC system's performance, three heater configurations use waste heat from the ORC turbine exhaust, ejector, and engine waste heat to heat the working fluid. Renewable energy sources are the primary focus of most current research initiatives. The present research focuses on unique ORC and ERC systems, considered as combined power and cooling systems, with the goal of improving exergy performance at low temperatures. The suggested ORC–ERC can generate energy destruction of 69.85 kW at a source temperature of 155 °C, with an exergetic efficiency of 76.9% at the turbine. Setting the entrainment ratio at 0.5 results in a total sum unit cost of products (SUCP) of 465 $/kW‐h for the ORC–ERC. Furthermore, the 37.83% exergy destruction ratio introduces heat exchanger 2 (HE2) as the primary cause of the suggested ORC–ERC's irreversibility. A detailed parametric study reveals that altering the hot source temperature and entrainment ratio improves the system's SUCP. The current examination at high sink temperatures may be expanded to an advanced exergoenvironmental investigation.

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Thermodynamic and thermoeconomic performance analyses and optimization of a novel power and cooling cogeneration system fueled by low-grade waste heat

Cited by 27 publications

References 43 publications

Thermodynamic Performance Investigation of a Small-Scale Solar Compression-Assisted Multi-Ejector Indoor Air Conditioning System for Hot Climate Conditions

Thermodynamic Performance Investigation of a Small-Scale Solar Compression-Assisted Multi-Ejector Indoor Air Conditioning System for Hot Climate Conditions

Multi-Objective Optimization of Steam Power System Under Demand Uncertainty

Economic Analyses of a New Power and Cooling System at Low Temperature Applications

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